#include <bits/stdc++.h>
// 2025/07/16
// tag:
// Author: Forever
using namespace std;
using int64 = int64_t;

int n;
double a[16];

double f(double x)
{
    double ans = 0, t = 1;
    for (int i = n + 1; i >= 1; i--)
        ans += a[i] * t, t *= x;
    return ans;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    double l, r;
    cin >> n >> l >> r;
    for (int i = 1; i <= n + 1; i++)
        cin >> a[i];
    while (r - l > 1e-9) {
        double midl = (l * 2 + r) / 3;
        double midr = (l + r * 2) / 3;
        if (f(midl) > f(midr))
            r = midr;
        else
            l = midl;
    }
    cout << fixed << setprecision(5) << l << endl;
    return 0;
}